Solid-state lighting apparatus with filament imitation for use with florescent ballasts

ABSTRACT

A lighting apparatus includes a solid-state lighting circuit, a ballast connection port including first and second terminals and a filament-imitating impedance coupled between the first and a second terminals of the ballast connection port and to an input terminal of the solid-state lighting circuit. The filament-imitating impedance may be configured to transfer power at a nominal frequency of an output produced by the ballast and to provide an impedance between the first and second terminals of the ballast connection port that prevents shutdown of the ballast. In some embodiments, the filament-imitating impedance may vary with temperature, e.g., the filament-imitating impedance may be configured to imitate a temperature dependence of a fluorescent tube filament. The lighting apparatus may be included in a fluorescent lamp replacement lamp.

BACKGROUND

The present inventive subject matter relates to lighting apparatus andmethods and, more particularly, to lighting apparatus for use withfluorescent lighting ballasts.

Solid-state lighting arrays are used for a number of lightingapplications. A solid-state light-emitting device may include, forexample, a packaged light emitting device including one or more lightemitting diodes (LEDs). These may include inorganic LEDs, which mayinclude semiconductor layers forming p-n junctions, and/or organic LEDs(OLEDs), which may include organic light emission layers.

Solid-state lighting devices are commonly used in lighting fixtures,including task lighting, recessed light fixtures, ceiling mountedtroffers and the like. Solid-state lighting panels are also commonlyused as backlights for small liquid crystal display (LCD) screens, suchas LCD display screens used in portable electronic devices, and forlarger displays, such as LCD television displays.

Solid-state lighting devices may be attractive for retrofit/replacementapplications, where devices such as LEDs may offer improved energyefficiency, reduced heat generation, extended life and desiredperformance characteristics, such as certain color and/or colorrendering capabilities. For example, LED bulbs are commonly used toreplace incandescent bulbs in down lights and other applications toreduce energy consumption and increase time between replacements.LED-based replacements for fluorescent lamps have also been developed,as shown, for example, in U.S. Pat. No. 6,936,968, U.S. Pat. No.7,507,001, U.S. Pat. No. 8,089,213, U.S. Pat. No. 8,358,056 and U.S.Patent Application Publication No. 2008/0266849, which describe varioustypes of LED replacements for use in fluorescent light fixtures.

SUMMARY

Some embodiments provide a lighting apparatus including a solid-statelighting circuit, a ballast connection port including first and secondterminals and a filament-imitating impedance coupled between the firstand a second terminals of the ballast connection port and to an inputterminal of the solid-state lighting circuit. The filament-imitatingimpedance may include a capacitor. The capacitor may be configured totransfer power at a nominal frequency of an output produced by theballast and to provide an impedance between the first and secondterminals of the ballast connection port that prevents shutdown of theballast. In some embodiments, the filament-imitating impedance may varywith temperature, e.g., the filament-imitating impedance may beconfigured to imitate a temperature dependence of a fluorescent tubefilament. The lighting apparatus may be included in a fluorescent lampreplacement lamp.

In some embodiments, the filament-imitating impedance may furtherinclude a resistor coupled in parallel with the capacitor. In furtherembodiments, the filament-imitating impedance may further include atemperature-varying resistor coupled in series with the capacitor.

In further embodiments, the ballast connection port may include a firstballast connection port, the filament-imitating impedance may include afirst filament-imitating impedance, and the apparatus may furtherinclude a second ballast connection port including first and secondterminals and a second filament-imitating impedance coupled between thefirst and a second terminal of the second ballast connection port and toan input terminal of the solid-state lighting circuit.

Some embodiments of the inventive subject matter provide a lightingapparatus including a solid-state lighting circuit, a ballast connectionport including first and second terminals, a filament-imitatingimpedance having a first terminal coupled to the first terminal of theballast connection port and a low-frequency blocking impedance having afirst terminal coupled to a second terminal of the filament-imitatingimpedance and the second terminal of the ballast connection port and asecond terminal coupled to an input terminal of the solid-state lightingcircuit.

The low-frequency blocking impedance may include a capacitor. A resistormay be coupled in parallel with the capacitor. The solid-state lightingcircuit may include rectifier circuit having an input terminal coupledto the second terminal of the low-frequency blocking impedance and atleast one light emitting diode (LED) coupled to an output port of therectifier circuit. The solid-state lighting circuit may further includea matching circuit.

In still further embodiments, a lighting apparatus includes at least oneLED, a ballast connection port, a filament-imitating impedance coupledbetween first and second terminals of the ballast connection port and amatching circuit coupled to the filament-imitating impedance and the atleast one LED. The apparatus may further include a rectifier circuitcoupled between the at least one LED and the filament-imitatingimpedance. The matching circuit may include an inductor coupled inseries with the at least one LED and a capacitor coupled in parallelwith the output port of the rectifier circuit.

Further embodiments of the inventive subject matter provide a lightingapparatus including a solid-state lighting circuit, a ballast connectionport including first and second terminals configured to be connected toa ballast and at least one resistor coupled between the first and secondterminals and having a terminal coupled to solid state lighting circuitand configured to prevent a filament test shutdown of the ballast. Theresistor may have a resistance sufficient to limit current flow to alevel that prevents activation of a starter switch coupled to theballast connection port.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the inventive subject matter and are incorporated inand constitute a part of this application, illustrate certainembodiment(s) of the inventive subject matter. In the drawings:

FIG. 1 is a schematic diagram illustrating lighting apparatus with afilament-imitating impedance according to some embodiments;

FIG. 2 is a schematic diagram illustrating lighting apparatus using acapacitor as a filament-imitating impedance according to someembodiments;

FIGS. 3-6 are schematic diagrams illustrating lighting apparatus withvarious filament-imitating impedance configurations according to someembodiments;

FIG. 7 is a schematic diagram illustrating lighting apparatus with afilament-imitating impedance including a parallel combination of acapacitor and resistance according to some embodiments;

FIGS. 8-10 are schematic diagrams illustrating lighting apparatus with afilament-imitating impedance and blocking impedance according to variousembodiments;

FIG. 11 is a schematic diagram illustrating lighting apparatus with arectifier circuit and matching circuit according to some embodiments;

FIG. 12 is a schematic diagram illustrating lighting apparatus with a CLresonant matching circuit according to some embodiments;

FIG. 13 is a schematic diagram illustrating lighting apparatus with a CLresonant matching circuit according to further embodiments;

FIG. 14 is a schematic diagram illustrating a temperature-varyingfilament-imitating impedance according to some embodiments;

FIGS. 15 and 16 are schematic diagrams illustrating lighting apparatususing temperature-varying filament-imitating impedances according tosome embodiments;

FIG. 17 illustrates a fluorescent tube replacement lamp according tofurther embodiments.

DETAILED DESCRIPTION

Embodiments of the present inventive subject matter now will bedescribed more fully hereinafter with reference to the accompanyingdrawings, in which embodiments of the inventive subject matter areshown. This inventive subject matter may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the inventive subject matter to those skilled in theart. Like numbers refer to like elements throughout.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present inventivesubject matter. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. It will be further understood thatelements “coupled in series” or “serially connected” may be directlycoupled or may be coupled via intervening elements.

Spatially relative terms, such as “below”, “beneath”, “lower”, “above”,“upper”, and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation, in addition to theorientation depicted in the figures. Throughout the specification, likereference numerals in the drawings denote like elements.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinventive subject matter. As used herein, the singular forms “a”, “an”and “the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” “comprising,” “includes” and/or “including” whenused herein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this present inventive subjectmatter belongs. It will be further understood that terms used hereinshould be interpreted as having a meaning that is consistent with theirmeaning in the context of this specification and the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein. The term “plurality” is used herein torefer to two or more of the referenced item.

FIG. 1 illustrates a lighting apparatus 100 according to someembodiments. The apparatus includes at least one ballast connection port101 including first and second terminals 101 a, 101 b. The terminals 101a, 101 b may comprise, for example, pins that are configured to beconnected to a fluorescent lamp connector (e.g., a tombstone connector)that provides electrical coupling to a fluorescent lighting ballast. Theapparatus 100 may also include a second port 102 with similar terminals102 a, 102 b for use in, for example, bi-pin fluorescent tubereplacement applications.

A filament-imitating impedance 120 is coupled between the first andsecond terminals 101 a, 101 b. A solid-state lighting circuit, hereshown as LED lighting circuit 110 (which may include one or more LEDsand associated circuitry for driving the same), is coupled to thefilament-imitating impedance 120 and the second terminal 101 b. The LEDlighting circuit 110 may also be coupled to the terminals 102 a, 102 bof the second ballast connection port 102, either directly or viaintervening circuitry.

According to some embodiments, the filament-imitating impedance 120 isconfigured to provide an impedance that mimics behavior of the filamentof a fluorescent lamp. In particular, the filament-imitating impedancemay be configured to present an impedance between the first and secondterminals of a ballast connection port that mimics the impedanceprovided by a filament of a fluorescent lamp, while at the same timeallowing power transfer between the ballast connection port 101 and theLED lighting circuit 110 so that the one or more LEDs of the LEDlighting circuit 110 may be driven by the ballast. In particular, somefluorescent lighting ballasts may be configured to detect the state ofan attached lamp by monitoring the AC and/or DC impedance betweenterminals of pins connected to the ends of the filament, and may shutdown the ballast if the impedance indicates a failed/failing lamp. Thefilament-imitating impedance may mimic the impedance of a healthyfilament under such monitoring and, therefore, may prevent unwantedshutdown. As further shown, the LED lighting circuit 110 may beconfigured to provide a matching impedance between the first and secondballast connection ports 101, 102 that facilitates power transferbetween the ballast and the LED lighting circuit 110.

As shown in FIG. 2, a filament-imitating impedance may take the form ofa capacitor C1 coupled to the first and second terminals 101 a, 101 b ofthe first ballast port 101 and to a LED lighting circuit 110. Thecapacitor C1 may be sized such that it presents a relatively lowimpedance above a certain frequency corresponding to the nominal outputfrequency of the ballast while still providing an impedance sufficientto imitate the filament impedance of a fluorescent lamp and, thus,prevent shutdown due to failure of a filament test by the ballast. Inthis manner, filament imitation may be provided while maintainingefficient power transfer to the LED lighting circuit 110 The LEDlighting circuit 110 may present an impedance that approximately matchesan output impedance of the ballast at the ballast's nominal frequencysuch that power transfer to the LED lighting circuit 110 may beoptimized. According to some embodiments, the capacitor C1 may provide acapacitance between the first and second terminals 101 a, 101 b of theballast connection port 101 that is in a range from about 0.1 μF toabout 4 μF.

Various embodiments may provide differing arrangements offilament-imitating impedances. For example, FIG. 3 illustrates alighting apparatus 300 including a first filament-imitating impedance320 a coupled between a first and second terminals 101 a, 101 b of afirst ballast connection port 101 and a second filament-imitatingimpedance coupled between first and second terminals 102 a, 102 b of asecond ballast connection port 102. As shown in FIG. 4, a lightingapparatus 400 may use such an arrangement implemented using first andsecond capacitors C1, C2. As shown in FIG. 5, a lighting apparatus 500may include respective filament-imitating impedances 520 a, 520 b, 520c, 520 d coupled to respective terminals 101 a, 101 b, 102 a, 102 b offirst and second ballast connection ports 101, 102. As shown in FIG. 6,such an arrangement may be implemented using respective capacitors C1,C2, C3, C4. Along the lines discussed above, these arrangements mayprovide capacitances between the first and second terminals 101 a, 101 bof the first ballast connection port 101 and between the first andsecond terminals 102 a, 102 b of the second ballast connection port 102that are in a range from about 0.1 μF to about 4 μF. The LED lightingcircuit 110 may provide a matching impedance between the first andsecond ballast connection ports 101, 102 as described above.

According to further embodiments illustrated in FIG. 7, a lightingapparatus 700 may include a filament-imitating impedance 720 thatincludes a capacitor C1 and a resistor R1 connected in parallel with thecapacitor C1. Some fluorescent lamp ballasts are configured to detect aDC resistance between pins connected to ends of a filament, and mayprevent operation of the lamp if the DC resistance is too great. Theresistor R1 may provide sufficient continuity between the terminals 101a, 101 b to prevent such a shutdown. According to further embodiments,the resistor R1 may have a resistance operative to limit current throughan attached starter circuit (not shown) to inhibit starter operation,i.e., the resistor R1 may provide a resistance sufficient to reduce orprevent glow discharge in the starter such that a bimetallic switch inthe starter remains open. Appropriate resistor values for T8 replacementapplications, for example, may be in a range from about 1 k ohms toabout 50 k ohms.

FIG. 8 illustrates a lighting apparatus 800 according to someembodiments of the inventive subject matter. A filament-imitatingimpedance 820 is coupled to a first terminal 101 a of a first ballastconnection port 101. A low-frequency blocking impedance 830 is coupledbetween the second terminal 101 b of the first port 101 and an LEDlighting circuit 110. The filament-imitating impedance 820 is configuredto present an impedance to the ballast that has characteristics similarto those provided by a filament of a fluorescent lamp and may take theform, for example, of the filament-imitating impedances described abovewith reference to FIGS. 1-7. The blocking impedance 830 is configured toblocks a lower frequency component that may be provided by the ballast,such as a DC offset produced by the ballast. In some embodiments, theapparatus 800 may be configured for operation only with high-frequencyelectronic ballasts, and the blocking impedance 830 may be configured toblock a 60 Hz component so that, if the apparatus 800 is incorrectlyconnected to a magnetic ballast, transfer of power to the LED lightingcircuit 110 may be reduced or prevented, thus preventing damage and/orimproper operation.

In some fluorescent replacement lamp applications, the arrangement ofthe filament-imitating impedance 820 and the blocking impedance 830 mayfacilitate installation without concern about the orientation of thelamp with respect to the lamp connectors. A typical fluorescent tube issymmetrical, i.e., the two pins on the end of the tube areinterchangeable in function. In some fixtures, one of the pins will beconnected to the ballast, while the other of the pins will be connectedto a starter circuit. Installation of a replacement lamp along the linesof FIG. 8 in such a fixture may result in the first terminal 101 a beingconnected to the ballast and the second terminal 101 b being connectedto the starter, such that the filament-imitating impedance 820 may alsoprovide a low-frequency blocking function. However, if the pins 101 a,101 b are reversed, the ballast may be connected to the second terminal101 b a rather than the first terminal 101 a. In this arrangement, thefilament-imitating impedance 820 would still provide filament imitation,but would not provide the desired low frequency blocking. Such blockingwould be provided by the blocking impedance 830. FIG. 9 illustrates anexemplary lighting apparatus 900, in which filament-imitating andblocking impedances are provided by respective capacitors C1, C2.

According to further embodiments illustrated in FIG. 10, a lightingapparatus 1000 may include a filament-imitating impedance 1020 includinga capacitor C1 and a low-frequency blocking impedance 1030 including acapacitor C2 as described above. The filament-imitating impedance 1020may also include a resistor R1 coupled in parallel with the capacitorC1. Some fluorescent lamp ballasts are configured to detect a DCresistance between pins connected to ends of a filament, and may preventoperation of the lamp if the DC resistance is too great. The resistor R1may provide sufficient continuity between the terminals 101 a, 101 b toprevent such a shutdown. According to further embodiments, the resistorR1 may be sized to limit current through an attached starter circuit(not shown in FIG. 2) to inhibit starter operation as described above.As also shown in FIG. 10, an additional resistor R2 may be connected inparallel with the blocking capacitor C2. The resistor R2 may beconfigured to discharge a DC voltage that may develop across theblocking capacitor C2 when the apparatus is used with certain types ofelectronic ballasts.

FIG. 11 illustrates a lighting apparatus 1100 according to furtherembodiments. The apparatus 1100 includes a first filament-imitatingimpedance 1120 a that includes a resistor R1 and a capacitor C1 asdescribed above coupled to a first ballast connection port 101, and asimilar second filament-imitating impedance 1120 b including a resistorR3 and capacitor C3 coupled to a second ballast connection port 102. Ablocking capacitor C2 and associated resistor R2 couples the firstfilament-imitating impedance 1120 a to an input port of a rectifiercircuit 1112. A resonant matching circuit 1114 may couple an output portof the rectifier circuit 1112 to one or more LED(s) 1116. The resonantmatching circuit 1114 may be configured to provide an impedance betweenthe connection ports 101, 102 that enables an optimal or near optimalpower transfer to the one or more LED(s) 1116.

As shown in FIG. 12, the rectifier circuit may comprise a diode bridgecircuit 1212, the matching circuit may comprise a CL resonant circuit1214 including a capacitor Cf and inductor Lf, and the one or moreLED(s) may comprise one or more LED strings 1216. According to furtherembodiments illustrated in FIG. 13, a lighting apparatus may includefilament-imitating impedances 1320 a, 1320 b, 1320 c, 1320 d in the formof parallel combinations of capacitors C1, C2, C3, C4 and resistors R1,R2, R3, R4 coupled between respective ones of the terminals 101 a, 101b, 102 a, 102 b of first and second connection ports 101, 102 and arectifier circuit 1212. This arrangement may eliminate the need for aseparate blocking impedance.

It will be appreciated that the arrangements illustrated in FIGS. 11-13are provided for purposes of illustration, and that any of a variety ofother solid-state lighting circuits may be used in embodiments of theinventive subject matter. For example, some embodiments of the inventivesubject matter may use filament-imitating impedances in combination witha variety of different solid-state lighting circuits described in acopending U.S. patent application Ser. No. 13/749,082 (Attorney DocketNo. 5308-1954) entitled “LED LIGHTING APPARATUS FOR USE WITH AC-OUTPUTLIGHTING BALLASTS”, filed Jan. 24, 2013 and in copending U.S. patentapplication Ser. No. 13/943,455 (Attorney Docket No. 5308-1954TSIP)entitled “LED LIGHTING APPARATUS FOR USE WITH AC-OUTPUT LIGHTINGBALLASTS”, filed Jan. 24, 2013, the disclosures of which areincorporated herein by reference in their entirety.

According to further embodiments, a filament-imitating impedance may bea temperature-varying impedance. Some ballasts perform filament tests inwhich a filament is tested by measuring a “cold” impedance of thefilament before energizing, and then testing the filament impedanceafter the filament has been energized and heated up. If the change inimpedance between the two temperatures fails to meet a predeterminedcriteria, the ballast may prevent operation. FIG. 14 illustrates afilament-imitating impedance 1400 including a capacitor C1 and resistorR1 along the lines described above, along with a parallel combination ofan additional resistor R2 and a positive temperature coefficient (PTC)resistor U1 coupled in series with the capacitor C1. The PTC resistor U1has a resistance that increases as current flows through the PTCresistor U1 and heats it up. Such an arrangement can be used toaccommodate such a test and prevent shutdown due to failing the test.

FIG. 15 illustrates use of such a filament-imitating impedance in alighting apparatus 1500 that includes a rectifier circuit 1211, matchingcircuit 1214 and LED string(s) 1216 along the lines discussed above withreference to FIG. 12. A first filament-imitating impedance 1520 aincludes a capacitor C1, resistors R1, R2 and a PTC resistor U1, and iscoupled to a first terminal of an input port of the rectifier circuit1212 by a blocking circuit 1530 including a capacitor C1 and a resistorR5. A second filament-imitating impedance 1520 b includes a capacitorC2, resistors R3, R4 and a PTC resistor U2 and is coupled to a secondterminal of the input port of the rectifier circuit 1212.

FIG. 16 illustrates another use of a temperature-varyingfilament-imitating impedance in a lighting apparatus 1600 that includesa rectifier circuit 1212, matching circuit 1214 and LED string(s) 1216along the lines discussed above with reference to FIG. 13. A firstfilament-imitating impedance 1620 a includes capacitors C1, C3,resistors R1, R2, R5 and PTC resistor U1, and a secondfilament-imitating impedance 1720 b includes capacitors C2, C4,resistors R3, R4, R6 and a PTC resistor U2, coupled to respectiveterminals of an input port of the rectifier circuit 1212.

As noted above, lighting apparatus as described above may be used influorescent lamp replacement applications. FIG. 17 illustrates afluorescent tube replacement lamp 1700 according to some embodiments.The lamp 1700 includes a tubular housing 1710 including a translucentportion 1710 a and end caps 1720. The lamp 1700 includes first andsecond ballast connection ports 1701, 1702 at respective ends of thehousing 1710. The first ballast connection port 1710 includes pins 1701a, 1701 b and the second ballast connection port 1702 includes pins 1702a, 1701 b. LEDs 1740 of an LED string may be mounted on a substrate 1730positioned within the housing 1710, Coupling circuitry 1750 may besupported by the substrate and connect the LEDs 1740 to the port pins1710 a, 1701 b, 1702 a, 1702 b. The coupling circuitry 1750 may includeone or more filament-imitating impedances, a low-frequency blockingimpedance, a rectifier circuit and a resonant matching circuit asdescribed above.

It will be appreciated that lamps according to some embodiments of theinventive subject matter may take any of a variety of other forms thanthe tube type lamp shown in FIG. 17. For example, some embodiments maybe configured to for use in fixtures that utilize circular (e.g., T9)lamps or non-integrated compact fluorescent lamps.

In the drawings and specification, there have been disclosed typicalembodiments of the inventive subject matter and, although specific termsare employed, they are used in a generic and descriptive sense only andnot for purposes of limitation, the scope of the inventive subjectmatter being set forth in the following claims.

What is claimed is:
 1. A lighting apparatus comprising: a solid-statelighting circuit; a ballast connection port comprising first and secondterminals; and a filament-imitating impedance coupled between the firstand a second terminals of the ballast connection port and to an inputterminal of the solid-state lighting circuit.
 2. The apparatus of claim1, wherein the filament-imitating impedance comprises a capacitor. 3.The apparatus of claim 2, wherein the capacitor is configured totransfer power at a nominal frequency of an output produced by theballast and to provide an impedance between the first and secondterminals of the ballast connection port that prevents shutdown of theballast.
 4. The apparatus of claim 2, wherein a capacitance providedbetween the first and second terminals of the ballast connection port isin a range from about 0.1 μF to about 4 μF.
 5. The apparatus of claim 2,wherein the filament-imitating impedance further comprises a resistorcoupled in parallel with the capacitor.
 6. The apparatus of claim 2,wherein the filament-imitating impedance further comprises atemperature-varying resistor coupled in series with the capacitor. 7.The apparatus of claim 1, where the filament-imitating impedance varieswith temperature.
 8. The apparatus of claim 7, wherein thefilament-imitating impedance is configured to imitate a temperaturedependence of a fluorescent tube filament.
 9. The apparatus of claim 1,wherein the ballast connection port comprises a first ballast connectionport, wherein the filament-imitating impedance comprises a firstfilament-imitating impedance, and wherein the apparatus furthercomprises: a second ballast connection port comprising first and secondterminals; and a second filament-imitating impedance coupled between thefirst and a second terminal of the second ballast connection port and toan input terminal of the solid-state lighting circuit and configuredtransfer power between a ballast connected to the second ballastconnection port and the solid-state lighting circuit.
 10. A fluorescentreplacement lamp comprising the apparatus of claim 1, wherein the firstand second terminals of the ballast connection port comprise respectivefirst and second pins configured to be connected to a fluorescent lampconnector.
 11. A lighting apparatus comprising: a solid-state lightingcircuit; a ballast connection port comprising first and secondterminals; a filament-imitating impedance having a first terminalcoupled to the first terminal of the ballast connection port; and alow-frequency blocking impedance having a first terminal coupled to asecond terminal of the filament-imitating impedance and the secondterminal of the ballast connection port and a second terminal coupled toan input terminal of the solid-state lighting circuit.
 12. The apparatusof claim 11, wherein the filament-imitating impedance comprises acapacitor.
 13. The apparatus of claim 12, wherein the filament-imitatingimpedance further comprises a resistor coupled in parallel with thecapacitor.
 14. The apparatus of claim 12, wherein capacitor comprises afirst capacitor and wherein the low-frequency blocking impedancecomprises a second capacitor.
 15. The apparatus of claim 14, furthercomprising a resistor coupled in parallel with the second capacitor. 16.The apparatus of claim 11, wherein the solid-state lighting circuitcomprises: a rectifier circuit having an input terminal coupled to thesecond terminal of the low-frequency blocking impedance; and at leastone light emitting diode (LED) coupled to an output port of therectifier circuit.
 17. The apparatus of claim 16, wherein thesolid-state lighting circuit further comprises a matching circuit. 18.The apparatus of claim 17, wherein the matching circuit comprises: acapacitor coupled in parallel with the output port of the rectifiercircuit; and an inductor coupled between the capacitor and the at leastone LED.
 19. The apparatus of claim 18, wherein the at least one LEDcomprises at least one LED string.
 20. A fluorescent replacement lampcomprising the apparatus of claim 10, wherein the first and secondterminals of the ballast connection port comprise respective first andsecond pins configured to be connected to a fluorescent lamp connector.21. A lighting apparatus comprising: at least one LED; a ballastconnection port; a filament-imitating impedance coupled between firstand second terminals of the ballast connection port; and a matchingcircuit coupled to the filament-imitating impedance and the at least oneLED.
 22. The apparatus of claim 21, wherein the filament-imitatingimpedance comprises a capacitor.
 23. The apparatus of claim 22, whereinthe filament-imitating impedance further comprises a resistor coupled inparallel with the capacitor.
 24. The apparatus of claim 21, furthercomprising a rectifier circuit coupled between the at least one LED andthe filament-imitating impedance.
 25. The apparatus of claim 24, whereinthe matching circuit comprises an inductor coupled in series with the atleast one LED and a capacitor coupled in parallel with the output portof the rectifier circuit.
 26. A fluorescent replacement lamp comprisingthe apparatus of claim 21, wherein the first and second terminals of theballast connection port comprise respective first and second pinsconfigured to be connected to a fluorescent lamp connector.
 27. Alighting apparatus comprising: a solid-state lighting circuit; a ballastconnection port comprising first and second terminals configured to beconnected to a ballast; and at least one resistor coupled between thefirst and second terminals and having a terminal coupled to solid statelighting circuit and configured to prevent a filament test shutdown ofthe ballast.
 28. The apparatus of claim 27, wherein the resistor has aresistance sufficient to limit current flow to a level that preventsactivation of a starter switch coupled to the ballast connection port.29. The apparatus of claim 27, wherein the at least one resistorcomprises a single resistor directly coupled to the first and secondterminals of the ballast connection port.
 30. The apparatus of claim 27,wherein the at least one resistor comprises: a first resistor coupledbetween the first terminal of the ballast connection port and the solidstate lighting circuit; and a second resistor coupled between coupledbetween the second terminal of the ballast connection port and thesolid-state lighting circuit.
 31. A fluorescent replacement lampcomprising the apparatus of claim 27, wherein the first and secondterminals of the ballast connection port comprise respective first andsecond pins configured to be connected to a fluorescent lamp connector.